At least 12 people were killed and 15 others wounded after gunmen attacked a popular cafe in a town north of Baghdad, Iraqi officials said Friday.

Officials said three gunmen attacked the coffee shop in the mainly Shi'ite town of Balad, shooting into the crowd shortly after midnight Thursday. Once police arrived at the scene, two of the attackers detonated suicide vests.

Balad, about 80 kilometers north of Baghdad, is under heavy security. The attackers would have had to pass through three police checkpoints before reaching their target, police sources told Reuters.

The officers spoke on the condition of anonymity as they were not authorized to speak to the media.

This attack follows a two-day wave of bombings in the capital that have left at least 80 people dead. The Islamic State group claimed responsibility for those attacks.

Earlier this week, Major General Gary Volesky, the top U.S. ground forces commander in Iraq, said Islamic State insurgents are "getting weaker and weaker" in Iraq, despite the jihadists carrying out the deadly attacks in Baghdad.

Volesky, speaking from Iraq to reporters at the Defense Department outside Washington, discussed the Iraqi campaign to reclaim territory held by Islamic State and the impending Iraqi effort to retake the northern city of Mosul.

He said Iraqi forces are making "great progress" in reclaiming land lost to the insurgents.

In recent weeks, the United States has said Iraqi forces and others fighting Islamic State in Iraq and Syria have reclaimed 40 percent of the lands once held by the jihadists.

Volesky offered no timetable for an Iraqi attack on Mosul, which Islamic State fighters have held for two years. But he said Iraqi forces, supported by U.S. trainers and advisers, are now positioned 35 to 40 kilometers south of the city.

It is “the farthest north [Iraqi forces have advanced] since [the Islamic State group] came over,” he said during a news briefing to Pentagon reporters.